1. Field of the Invention
The invention relates generally to the performance of operations by robots in environments which are hostile to humans and, more particularly, it relates to a method of putting a robot into position in an operating zone within a containment vessel including an access opening. For example, inspection and maintenance operations are often carried out by robots in nuclear plants where people are allowed only under very stringent safety conditions. One such situation occurs in the maintenance of steam generators in pressurized-water nuclear power stations.
2. Summary of the Prior Art
For these operations, it has already been proposed to use a tool-carrying robot consisting of an articulated arm controlled by a logic unit. The base of the robot is fixed to a stand located underneath the vessel of the steam generator and having a certain amount of freedom of movement, thereby enabling the robot to be moved towards the access opening of the vessel and through which it reaches its operating location.
This known arrangement has a number of drawbacks. The stand constitutes a particularly heavy piece of equipment and does not allow one to have a known and stable frame of reference in time. Also, positioning of the robot device is a relatively long process, which is disadvantageous in terms of the period of time for which the plant may be shut down.